(i) Field of the Invention
The present invention relates to an apparatus and a method for generating an image, which apparatus and method are utilized in an ITS (Intelligent Transport System) field such as a car navigation system, a virtual reality (VR) field such as a virtual city, a three-dimensional computer graphic (3DCG) field such as a three-dimensional modeling, and so on.
(ii) Description of the Related Art
Recently, techniques of fetching a texture image (hereinafter, called as “the image”) of a large-scale environment such as an urban area into a computer by using a camera or a range sensor and utilizing the image fetched as such in an ITS field or a VR field are actively carried out as disclosed in M. Hirose and E. Takaaki. Building a virtual world from the real world. In proceedings of International Symposium on Mixed reality, pages 183-197, March 1999, for example.
In this case, a technique of efficient fetching and acquiring images into a computer is tried. Although acquisition of images is relied on the manpower until now, there is a limit for labor reason when acquiring images by using the manpower. Therefore, as a technique of automatic acquisition of images, there are proposal such as a technique based on aerial photographs, a technique using an omni-directional camera as disclosed in Y. Onoue, K. Yamasawa, H. Takemura, and N. Yokoya. Telepresence by real-time view-dependent image generation from omni-directional video streams. Computer Vision and Image Understanding, 71(2): 154-165, August 1998, for example, a technique using a combination of a plurality of cameras, and so on.
Further, in relation to the technique of automating acquisition of images, there are proposal such as a technique called as an IBR (Image-Based Rendering) as disclosed in Shenchang Eric Chen. QuickTime® VR—An Image-Based Approach to Virtual Environment Navigation. COMPUTER GRAPHICS Proceedings, Annual Conference Series, pages 29-38, 1995 A. Lippman Movie-maps. An application of the optical videodiscs to computer graphics. In Proceedings of ACM SIGGRAPH '80. pages 32-43, 1990. and T. Takahashi, H. Kawasaki, K. Ikeuchi, and M. Sakauchi. Arbitrary view position and direction rendering for large-scale scenes. In Computer Vision and Pattern Recognition, volume 2, pages 296-303, June 2000., for example or a formation of an image called as an EPI (Epipolar Plane Image) as disclosed in R. Bolles, H. Baker, and D. Marimont. Epipolar plane image analysis: an approach to determining structure from motion. Int. J. of Computer Vision, 1: 7-55, 1987, for example.
However, in case of the technique based on the aerial photographs and the technique using the omni-directional camera, there are limits resulting from resolutions of images, directions of textures to be imaged and so on. On the other hand, the technique using a combination of a plurality of cameras does not have the limits in the technique based on the aerial photographs and the technique using the omni-directional camera, however, it is difficult to generate one image by integrating a plurality of images, and it is also difficult to acquire an image in a large-scale environment substantially free from distortions without information (correction) of shapes such as depth information.